


Years Ago

by BabyMephista



Category: Dr. STONE (Anime), Dr. STONE (Manga)
Genre: Alpha!AsagiriGen, Alpha/Beta/Omega Dynamics, Alpha/Omega, Anal Fingering, Anal Sex, Angst with a Happy Ending, Canon Compliant, Fluff and Smut, M/M, Omega!IshigamiSenku, Sex
Language: English
Status: Completed
Published: 2021-03-01
Updated: 2021-03-01
Packaged: 2021-03-11 22:34:30
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 6,445
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/29750016
Author URL: https://archiveofourown.org/users/BabyMephista/pseuds/BabyMephista
Summary: Years ago, the Kingdom of Science expanded itself from a quiet, cozy village to the American Continent.Years ago, Ishigami Senku led them to the biggest adventure of their lives.Years ago, Asagiri Gen, the most superficial man on earth, discovered he was hopelessly in love with a mad scientist.
Relationships: Asagiri Gen & Ishigami Senkuu, Asagiri Gen/Ishigami Senkuu
Kudos: 26





	Years Ago

**Author's Note:**

> A humble present for my beautiful @holweed ♥ ILY THANKS FOR EVERYTHING YOU MADE FOR MY FIC ;_; ♥ 
> 
> Beta: my bby boi @meifuko uwu ♥

Years ago, the Kingdom of Science expanded itself from a quiet, cozy village to the American Continent.

Years ago, Ishigami Senku led them to the biggest adventure of their lives.

Years ago, Asagiri Gen, the most superficial man on earth, discovered he was hopelessly in love with a mad scientist.

When Shishio Tsukasa depetrified him as a tool for his own use and nothing more as he represented everything the taller man hated, Gen just went with the flow, nodding and being complacent because there was nothing and he didn’t want to be killed. The world now was a Stone World and he had the misfortune of being a spy for a guy he didn’t liked. And that was it until his first mission led him to an incredible mad scientist, a guy who apparently counted every second for 3700 years and scratched in the wood of a tree, the exact date he woke up. That was amazing, brilliant. Gen wanted to meet him. Ishigami senku….

Of course, he acted neutral around Tsukasa and his “pure hearted” men, he didn’t want them to suspect anything.

Then, a few days walking and tracking, he got to his goal. The guy already made lots of progress and was happily serving ramen to a congregation of people. A melon-headed little girl gave him a bowl hurriedly and all he had to do was to drawl “Ah, this is making me thirsty for a drink. Like, say, cola ~” and the rest, was history.Gen was safe and happy, even if he was slowly falling in love with a guy he never was going to have, to the lengths of making him an observatory for his birthday… which Gen led Senku to tell him but, he was fine with it, as long as Senku allowed him to be by his side. Hah…what a depressive thought. 

Another thing was Senku’s scent. He smelled like rich liquid caramel and sometimes, when he was very stressed, the scent would change to a slightly burnt caramel mixed with some kind of volatile chemical. That was soo like him. Gen on the other hand smelled like flowers, mixed and successfully hidden among the one’s he always carried with him, swearing to never reveal his second gender to anyone, not even Senku. He needed most parts of himself has a mystery in order to have more cards on his deck when time required so.

The only problem with that was to run away every time Senku was in heat and try to calm down his inner alpha screaming at him to claim the poor, struggling omega. The logic saying that if he claimed the scientist then he wouldn’t have to suffer those body wrecking heats only unmated omegas had.But the reason within him was stronger, he wasn’t a mentalist for nothing. So, it went like that, routine-like even. Uneventful. Until it happened, until he fucked up, until his secondary gender proved to be a bother.

Years after the so called “Stone Wars” they traveled where they could, as far as science would take them. Treasure Island was such and adventure, he got petrified again and revived by the love of his live, losing his characteristic scar but that was okay, all of them decided on paint them back until humanity was restored, like battle scars.

Gen felt warm inside him while he pondered, thinking of all those people as his true family.

Not even a long time passed and they were back into it again, tracking the whyman, an entity copying Senku’s voice sounding like a distorted radio, a dark Senku they joked.

After a few days traveling overseas they found themselves in the American Continent, more precisely, North America… and, they were ambushed by their tenants. They had a professional scientist leading them and gunpowder. The Science Kingdom was at disadvantage.

Gen thought he was being left behind, that everyone improved but him so he made his choice to be noticed by the soldier, pretending to be an innocent magician just to infiltrate, putting his mentalist’s abilities to good use and try to prove himself he could be more than useful, even at the point of going through a lie detector without a scratch. How they dare to challenge a mentalist?

He listened to them speak in English, blood running cold at the adult scientist asking the soldier named Stanley Snyder to kill the enemy scientist. Senku wasn’t an enemy! Why? Panic went through his veins and when Dr. Xeno asked a name to match he blurted “ _DR TAIJU IS OUR LEADER SCIENTIST!”_ In hopes to give his allies more time and, trying to put someone stronger in the line, knowing that Senku wouldn’t resist.

He hoped, really hoped, to run away from that place soon and such wish was granted when the power team entered the building, catching Xeno as a hostage and rescuing him once and for all.

The way to the boat they stole from Xeno was a little bit frantic, there were people everywhere, even some new faces, one he didn’t like at all but hey, what can he do? Pretend, of course, as the professional mentalist he was.

Seeing Senku after a long time affected him, though, and knowing they were being pursued and that the enemy forces wanted him dead kicked his alpha instincts but he could live with that. And, honestly, he was surprised Dr Xeno didn’t say a thing about him being an alpha, maybe the guy thought everybody knew and that wasn’t something important anyways still, the way those black void eyes stared at him said he DID know his other secret, his love.

Arriving on South America was something good and bad at the same time. He was thrilled to have some ground on his feet for he was anxious and, even if he and Senku didn’t talk that much, he stayed behind him, contemplating as per usual. Even when the young scientist presented the idea of motorcycles, he laughed but helped anyways, making the older scientist help as well.

Dr. Chelsea was a nice breath of fresh air too, the ever-blunt woman made him loose a little bit. That’s why he felt so happy when the bikes passenger arrangement was sorted. He got to drive with her and his dear Senku.

The ride on the first bike of the Stone World was cranky and he was oh so happy. Even if Stanley was pursuing their tracks to assassinate them, it felt really good how they miss them and had their plane ruined by the love of his life.

Ah, Senku was really one of a kind. He wanted to mate him so badly and have lots of pups with Senku’s eyes and hair, teach them to love science and magic, be happy like a family. But unfortunately, that was impossible.

— _Senku and I are in a very mature relationship ~_ _—_

Luna’s annoying voice interrupted his train of thoughts. Senku would never love her back. An airheaded girl who had to buy her place in a school, who needed to be saved everytime, who had the nerve to blackmail his dear Senku-chan into a relationship? Although he didn’t knew the details of it, why Senku would accept such a thing? Ugh, he was nearing thin ice although not giving it away. But close.

— _It doesn’t look like that to me, you’re not dating!_ _—_

Dr. Chelsea’s blunt statement shook him and made him laugh audibly. Thank god no one noticed it was a laugh of pure malice at the pink haired girl’s dejected reaction, the alpha within urging him to put that stupid beta on her place for trying to take his omega.

No, he wasn’t like that. Senku wasn’t his, Senku wasn’t just an omega. Gen was always proud, even before petrification, of his ability to not fit into the alpha stereotype going as far as hiding it. No one knew, nor in that century or this one. And he wanted to keep it that way. 

Further on their journey, the Science Kingdom finally found a Medusa dumpster. None of them worked and was something mysterious so they did what they always did. Destroyed some of them, analyzing every component and even communicating with their people still staying in USA, an alliance of peace formed between them and the remaining people there.

Gen and Yuzuriha took the spotlight with their hard work and after that they decided to continue.

After that a series of events happened. The military unit tracking them, Chrome having the fantastic idea of covering the entire boat with Medusas to avoid being noticed and lots of dangerous ways that led them to their final destination: Araxa.

Marveling aside, they continued the journey like it was an adventure out of a videogame and, even if he noticed something off about Senku since they left North America, Gen decided not to pry too much. The scientist was probably exhausted, he sucked at physical exercise and wasn’t used to this kind of trip. Or maybe he was nearing his heat? Either way it was fine, nothing out of the ordinary.

Or so he thought, until they finished the “Fortress Medusa”, finally having a little bit of peace and for a while he forgot about the danger as they built around the place to make it safer and more strategic, even letting himself go about secondary genders, dark thoughts and unrequited love. He was ready to move on and act more like Senku’s right hand man, just like old times.

And it was the perfect idea until he entered the makeshift hut Senku was resting in to find the scientist half naked but it wasn’t that what Gen found difficult to swallow no, but the big marks on the guy’s chest, fresh wounds that the latter touched and hissed at. What was going on?

_—Senku-chan, what are those? When did you get them? —_

Gen was being frantic, panicking about not being able to recall a time when Senku got this hurt, damn it looked so bad!

_—Gen… I…—_

Shit, Senku knew Gen would overreact if he found the wounds but he never thought he risked being discovered. The scientist completely forgot about that detail with his heat being so close to the point of not being able to form a coherent thought to justify what he hid.

_—Stanley shot me, I couldn’t avoid the bullets altogether but I did something quickly to prevent dying, after that, Luna gave me first aid and we just never talked about it again. —_

That was the truth but the mentalist wasn’t having it. So, that’s the thing Luna blackmailed Senku with. Bitch, stupid bitch.

_—And you didn’t think about telling your right-hand man you were about to die?! Why in the world you hid this from me?! —_

Gen was losing control and working himself up, panting increasing as well as his teeth trying to show themselves, his inner alpha and him, both angry and hurt… did Senku even trust him at all? He wanted to leave, now. 

Senku was nervous, something about Gen’s deeper voice and hurt statement made his stomach churn. He didn’t want the other to think that!

_—No, Gen, that’s not it! —_

The scientist, desperate to tell him he’ll never do something like not trust in him, grabbed the mentalist by the shoulder, but the response he got to it wasn’t like anything Senku expected.

Gen’s pupils were dilated, he swore he could feel shivers down his spine, those kinds of shivers only omegas facing an authoritative alpha could feel and everything happened so quickly he almost fell backwards. Gen was scaring him.

_—DON’T TOUCH ME, YOU MADE CLEAR THAT YOU DON’T TRUST ME, I DON’T WANT YOU NEAR ME, ISHIGAMI SENKU!. —_

Gen’s commanding voice shook the poor omega to the ground and pinned him in place, eyes watering in sadness, confusion and realization: Asagiri Gen was an alpha, and he used his alpha voice to submit him.

The young scientist’s world was upside down, he wanted to fight back and tell him he was wrong but his stupid hormones obeyed the command. He couldn’t believe Gen would do such thing to him.

Senku swore he could hear his heart shattering to pieces at the cold stare he never thought he could receive from his mentalist. That thing didn’t even look like Gen. Shit.

Why did he never realize the guy was an alpha? Goddamnit.

Well, it’s not like that could solve anything as he saw the mentalist’s back disappearing in front of him. He wanted to cry, to scream at the stupid guy for hiding such important information but… he did the same and now their trust seemed to be broken for good, and he didn’t even have the time to mourn about the person he loved the most breaking his heart and asking him to be far away from him.

Heat suppressed and heart laying on the ground, Ishigami Senku took a deep breath and got ready for the final battle against Stanley’s military unit.

*---------------------------------*

The battle against them wasn’t that much of a battle. When the power trio, Tsukasa, Hyoga and Kohaku, tamed Maya, guns weren’t a problem once they connected the first punch. Stanley though, was the toughest to bring down. Hyoga, ever the heartless one, threatened to cut Xeno in half, going as far as hurting him in the neck with his spear to prove his point and, Stanley, surrounded, had to give up. The bond he shared with his omega haunting him. He could feel Xeno’s distress, sadness, fear of death now he was at mercy of the only man who could kill like breathing in the Kingdom of Science.

Senku wasn’t pleased with this development but they couldn’t think of anything else. It was a kill or be killed kind of situation but at the end, everyone lived, at least for now, everyone was ready to come back and he wanted to make revival fluid to continue the journey all around the world.

Out of the corner of his eyes, he saw Gen looking at the sea, absent minded and lonely. He feared that the mentalist wouldn’t come with them once settled in Corn City, inevitably losing contact with him for good.

He didn’t know why he cared or well, he did.

Senku was in love with Gen since the latter plotted that birthday surprise and told him his feelings. He, ever the emotionally constipated dude, didn’t got it but that was okay, he still had Gen… now, this felt like a goodbye.

The scientist dried a few stray tears. He wanted, for the first time in his life, a proper nest.

*----------------------------------*

Back at Corn City, everyone was full of emotions and I miss you’s, Taiju ran to Yuzuriha, holding her dearly to his chest while the girl cried her heart out, they would probably mate today… even with the tension between them and the americans, everything was fine or at least almost everything.

Gen pretended to be okay and smiled broadly, excusing himself later to disappear within the castle. His guts told him the mentalist would start distancing himself from everyone and that thought almost made him tear up. Damn his heat was really close, he’s never this hormonal. Well, he got his heart broken too, that was a principal factor.

He shook his head, deciding on lock the prisoners first and then look for a room in the vast place to spend his heat on. Thank god Xeno was this extravagant and built a fucking fortress full of rooms and stuff, which is why, Xeno and Stanley, along with all the military unit, were disposed in a dungeon of their own making. He could deal with them later but for now, a nest.

Senku explained the situation to Taiju and Yuzuriha and asked them to deal with the people the next few days. He wasn’t embarrassed to be an omega but wasn’t to keen on shouting to the wind he was about to go on heat. Nope.

That being solved, he started walking through the halls. Xeno designed a few rooms to hold his scientific progress, guns and chemicals, so the first ones were out of the question… maybe further down?

Ah, he was running out of time. The first wave was around the corner, he thought, when something inside his stomach churned painfully and he almost fell off the stairs. Senku clutched himself and sat on the floor, panting and feeling helpless. He was too far away to ask for help to go to a room and he couldn’t leave his bags with provisions behind, he needed them in order not to starve and die between waves. Damn.

He was starting to panic at the sudden urge to pleasure himself, this couldn’t be happening, not like this. And the scientist was about to abandon all hope when a sweet, alluring smell of flowers and musk filled his senses. Gen… Gen… he was here….

_—Senku-chan?!_ — The alpha approached him, but he wasn’t having it and kicked his feet, growling at the mentalist who had the nerve to talk to him after what he did.

_—Go away, mentalist, don’t you fucking dare!_ — He screamed baring his own teeth and he wasn’t crazy; Gen was crying and shrinking but not making a single move to go away, he was worried. Senku didn’t give a shit so he hissed.

_—Senku-chan please_ …—He inhaled, inhaling sweet burnt caramel, self-control wavering. — _At least let me help you, you can’t spend your heat in the ground… tell you this, let me and you’ll never have to see me again and that’s a promise, deal?_ —Gen didn’t want that but he wanted Senku to be safe, he still loved him with all his heart, he couldn’t leave the person dearest to him like that.

Senku was trying to calm down and accept the help, even if he didn’t like one-bit hearing Gen saying that, confirming his suspicions about the mentalist drifting away. No, he couldn’t accept that.

_—F-Fine…. —_ He blurted out, retrieving his fangs while extending both arms to the alpha who took him up efficiently, flower scent calming his inner omega.

He wanted to cry, lulled to calmness by the one who hurt him the most.

Gen ignored the tremors the best he could, walking with the omega to a safe space, a room, and he opened the door. The place showed signs of belonging to someone, a wood mattress and primitive blankets. Probably belonged to one of the prisoners. He placed the scientist gently in the bed, helping him to get rid of the bags full of stuff.

_—It wasn’t that hard right? ~ Now you can stay here until it passes and I’ll fullfill my promise…._ —Gen was trying to look calm and collected but the tremor in his voice did nothing to hide his state so he tried to shake himself out of it and smiled a pained smile. _— I guess this is goodbye, My Dear Senku…_ — He didn’t have the right to cry so the mentalist did everything in his power to remain unaffected, standing up after saying it, although he couldn’t go that far because a hand clutched his robe firmly.

_—You don’t get to say those things after everything we’ve been through together… after you betrayed Tsukasa to join me, moved heaven and earth to make me a fucking observatory for my birthday… you, why can’t you be honest for once?_ — Tears were streaming down Senku’s cheeks, anguish consuming the scientist as he tried to find answers only the man in front of him could give.

Gen couldn’t bear to see him that way, to be the cause of Senku’s suffering and wanted to disappear so the other wouldn’t have to worry about it anymore but, his instincts prevailed, his alpha wanted to soothe the struggling omega so he did; Retrieving and taking a seat on the bed, embracing the scientist in his arms.

_—I-I’m sorry for snapping at you like that, I don’t know why I acted that way… I’m always in control and knowing you hid something that important made me lose my mind… I know that’s not an excuse but please, believe me, I didn’t want to use my alpha voice on you, I would never want that!_ —Gen rocked and scented him, trying to convey his feelings

_—I was so scared, you almost die… you’re so reckless I’m always wondering if I’ll get to see you when you’re old… god, I love you so much but it pains me to think you don’t trust me enough..._ —The mentalist sobbed and officially, both of them were a mess.

Senku couldn’t think straight, he knew all along Gen would never do something like that on purpose but still hurt. To be loved like this by his most important person and still having to say goodbye, that wasn’t fair. 

_—You didn’t tell me you were an alpha and had the nerve to talk about trust? I can’t accept that._ —The omega snarled, still weak in the other’s embrace, feeling light as a feather for the constant scenting.

_—You got me there…_ —Gen sniffed and chuckled. — _But I had my reasons, I wanted to keep the most for myself so no one could use it against me, that’s the kind of job a mentalist does best…—_ Then, he inhaled, trying to find the right words. — _I was happy to just stay by your side, sharing little moments and try to keep you safe but this intense feeling overwhelms me to the point of losing control and I don’t like it…_ —He confessed, arms tightening around the other man’s figure.

_—You’re not the only one, don’t play the victim card on me because we both know I’m not up for your bullshit_. — Even though their conversation was so volatile and aggressive, Senku found himself deepening the contact, settling comfortably against the alpha. He wanted to blame his hormones but that wasn’t right. He was the one wanting to be closer. How could this be fixed? He wanted his mentalist back so badly.

_—I don’t play any card you don’t want me to play, Senku-chan, you heard me, right? I’m in love with you, I always have…—_ His hands started rubbing soothing circles on Senku’s back, earning a cute whine. If the context was another he could continue and see what happens. Now though, he needed to convince this man that he regretted all the wrong he caused between them. _—I just want you to forgive me…—_ He whispered, defeated. 

Senku, at his surprise, chuckled and retrieved his head from Gen’s chest, looking at him dead in the eye. Both men stopped crying a long time ago and now they were sharing an equally red rimmed stare. The scientist wanted to forgive him and tell him he loved Gen back, but he was so hurt. Still…

_—I heard you the first time…—_ He paused, forehead now touching Gen’s. — _And I love you too, God knows why_ …—Senku admitted, blushing a bit more, sensing his heat starting to act up again. — _But I’m not going to forgive your barbarian act back at Araxa, you know? Using alpha voice is something shameful, even if you didn’t do it on purpose…. You’d have to work hard to earn my trust again._ —The scientist sentenced, resolve crumbling at the mentalist’s response, which was a smile so bright he could barely stand to look at.

_—I p-promise! I’ll make it up to you as long as I live, I just want to be with Senku-chan, I want you to trust me and be mine… also be yours…_ —Gen blushed at his choice of words. Asking his love right before a heatwave, even if Senku was capable of consent and all, looked really convenient. He was feeling self-conscious about it.

The scientist laughed, how typical of Gen. Well, even if their relationship now was hard around the edges and a little bit broken, the both of them made up their minds. They wanted to be partners forever, mates…. Oh. That thought made Senku’s insides twist deliciously. Gen, his mate….?

_—Last chance, Mentalist. —Senku said, lips breathing on Gen’s. —Are you ten billion percent sure of your words? Do you want to be my mate, you insufferable bastard?_ —He smirked his signature smirk, a surprised noise swallowed by the other’s lips on his own. The only answer he needed.

And he knew it was risky but every cell and bone on his body craved to seal the bond right now. He couldn’t take it anymore and his body started a second wave, electricity like sensations wrecking through him.

_—G-Gen, please, my heat…—_ He whispered, voice breaking and failing him, panting was the only thing coming out of his lips besides the broken whimpers.

Senku started to sweat profusely, vision now clouded with lust and body instinctively curling around itself. Gen struggled to lay him down and think properly. This wasn’t the first time he got to smell the scent of Senku in heat but the first one together, in which the latter consented.

In which both of them would become mates for life.

He gulped, suddenly nervous. He could do it. Now, Senku was first and Gen needed to take care of him. His omega’s heat and pleasure were first. He repeated that as a mantra, standing and taking off his complicated layers of clothing, one by one and doing the same to the scientist although he was curled up really tight and was too difficult but Gen achieved it.

Both men were now naked. Things got suddenly too real.

Senku’s sobbing called him back to reality, the omega was suffering. He couldn’t take it.

_—I-I’m gonna prepare you, as sure as I am that your slick is enough, we can’t force it ‘kay?_ —Gen said, opening his legs and situating himself comfortably between them, Senku latched his arms immediately around him and pushed down to kiss him. Their first kiss.

It didn’t feel like in the movies, no fireworks or things exploding, not a single cliché thought about how things felt oh so right, none of that.

Instead, both men felt like the colors on the rainbow were painted again in their favorite ones, like the smell of the sweetest pastry ever; Gen remembered the struggle, the pain, what it took to be kissing him right now. The what if’s, the doubts, all of it, disappeared in the air. Senku felt all the emotions he read about on books but never thought he would be capable of experiment. He never loved anyone, he could never. Gen was his only exception.

Lips glided together harmoniously, kissing without hurry just savoring the moment. Even Senku, who was suffering because of a heatwave, had it in him to be slow and through, not even using tongue, not until Gen’s asked for entrance and he helplessly gave in.

All the love in the universe couldn’t compete with how much the desired each other as well, kiss now heated enough to send them rocking his bodies against each other like animals, alpha an omega not really controlling themselves and it was perfect. It was them.

Gen knew he needed to be through, prepare Senku and mate him, so he broke the kiss and left the omega whining capriciously at this. He was in the mood already, good.

_—I’ll start…._ — The mentalist said, an arm around the other man while his free hand caressed Senku’s slick drenched hole, a single finger pushing in too easily. God, he was getting past sentimental phase to a horny state so fast it could be problematic and the other’s little sounds didn’t help at all.

_—Gen…—_ The omega whispered, lower lip trapped now between his teeth as the alpha inserted two more fingers, knowing he was really dilated and trying to stretch him enough to take his cock.

Gen was big, he knew it although he didn’t care enough. Not that kind of guy, thank you very much.

But he didn’t want to hurt Senku, so the mentalist took his sweet time.

Up to the first knuckle, Gen experimented his sweet spot. A little nub he pressed enough to make the other man twitch violently, gorgeous dick spurting pre-cum massively, cute droplets falling down the shaft slowly. He felt his mouth water at the sight so he latched his lips to Senku’s nipples, the closer expanse of skin he could reach, as he insistently fucked him with his fingers in and out.

Senku was lost in pleasure but it wasn’t enough. His heat taking over his body as he drawled a series of high-pitched moans harbored by his own lustful state. The emptiness was starting to feel painful, even with the fingers his hole only wanted the alphas cock, call it instinct or whatever.

_—Just a little b-bit more I promise…—_ Gen called, tongue hitting the cute nipples, traveling down slowly. Senku’s dick was so gorgeous, so wet and twitching he couldn’t really help it as his mouth engulfed the shaft all the way to the base, making the omega scream and cum instantly down his throat.  
Gen swallowed it, fingers never ceasing to fuck Senku’s hole and noticing he was still hard. Damn. He licked his lips.

_—G-Gen please, I’m ready just… fuck me, I can’t take it anymore…p-please…—_ Senku was feeling overstimulated and hot all over, empty and emotionally unstable, he needed his alpha.

His alpha, how good that sounded.

Gen understood immediately and removed his fingers, licking them clean and enjoying the honeyed taste of his soon to be mate’s sweet slick.

_—Shush i’ll give it to you…. —_ The alpha whispered, aligning himself.

The moment Gen’s huge cock was close enough for Senku’s skin to feel the heat of it, his pink hole reacted by twitching and the alpha inserted just the tip, entering him little by little, amazed at the way the omega’s insides embraced his girth, like it was made for him.

Senku grabbed Gen by the nape of his neck almost violently and submitted the alpha to a needy, hot kiss, all tongue and teeth. He was so impatient to feel all of him.

Soon enough, the mentalist started moving and breaking the kiss to breath, looking at the fine man beneath him, flushed and wriggling, hips moving on their own as he desperately fucked himself into the alpha’s big cock.

Senku was a sight he’s lucky to have all for himself.

With that thought in mind, Gen started pistoning his hips and taking the omega’s legs to open them more, seeing his cock in and out of him, mesmerized…. How good it would feel to knot him….

_—You want my knot, baby? Want me to stay inside you forever?_ —He asked, voice rough and rich as he went as deep as he could but oh so slowly, just to torture the poor scientist and make him beg.

Senku only nodded his head, or he might’ve just shivered but to Gen that just was as good as a nod. Maybe that wasn’t a good idea for the man could get knocked up but ultimately, they’d pull through.

_—Give it to me…._ —The omega’s broken voice took him out of his trance and Gen really gave it to him, pushing to the hilt and making the boy beneath him scream and make those oh so cute expressions he never could get enough of.

For a moment, Gen brought a finger to touch at the skin stretched around his cock where he was still rapidly thrusting in and out, hungry for more. He was reaching a peak as his head felt light and the base of his knot started pulsing. Fuck. 

Senku was lost in pleasure, tongue out, drool all over his chin, a fucked-out expression and eyes rolled up at the back of his head. Nails digging harshly on Gen’s shoulder blades as the skin-on-skin insistent slap filled the room, making them both eager for more. The alpha wanted to bit Senku right now. Make him his once and for all, but first….

_—I want y-you to bite me first…—_ Gen slowed down again, making the omega whine and taking his face between his hands. He kissed his lips tenderly, conveying all his feelings on a single touch and Senku looked at him soberly, trying to regain conscience.

_—You s-sure, Gen? —_ He asked, voice broken and raspy, hopefulness in his scarlet eyes. This was it. After this there was not coming back, he and Gen would be bonded forever and finally be mates.

The bicolor haired man nodded, eyes full of emotions and just like that, he presented his neck to the waiting omega, flinching at the feeling of those pointy fangs biting on his flesh, growing even more hard inside the man. His hips moved on their own, provoking the latter to deepen the wound.

_—F-Fuck, Senku…._ —He growled, thursting idly as the omega lapped up the remains of blood in his neck, a pretty bitemark now adorning it.

He felt happy and now, he only needed to finish the deal, knot already swollen enough to enter him.

The first burn of the knot made Senku moan languidly, eyes rolling back and neck ready in position to be marked. He only adventured a single look to Gen who understood more than words could say to him.

The alpha went down and nuzzled his scent glands before licking them and, as he fucked him senseless, Gen deeply sank his teeth in that fair, pristine and soft milky skin, scarlet dropplets making their way down Senku’s neck as Gen bit him mercilessly, so sure of leaving a mark that would last a lifetime or two.

Neither of them realized the alpha was already coming inside his omega, filling him to the point of no return, knot securing safely all the seed inside him, pink hole squeezing and milking it dry.

As a few moments passed, after many, many licks to clean the blood off the younger man’s neck and clavicle, both men started to come down from their high. Happy because now they could feel the other in more ways than physical for the connection of their newly formed bond. Emotions now running free without the need of saying any word.

_—I know It’s awkward but we have to wait ‘till deflate so I can pull out, speaking of which uh…—_ Gen’s eyes widened comically at his realization. _— Senku-chan… I-I knotted you-- you know that, right!? and on your heat! Uh…_ —And before Gen could keep up with his babbling, Senku kissed him with the sole purpose to shut him up. He fucking knew this was dangerous and for being a scientist he was really irrational and impulsive, now the consequences were there and they had to deal with them.

It wasn’t that bad, he could get pregnant, okay, great. Which is the worst scenario? Xeno and the others were safely locked and he could monitor the making process of the revival fluid without having to be around too much. It would be just for a few months until he inevitably had to get bedridden and he was ten billion percent sure a child wouldn’t be something bad for them.

_—I’m probably going to get knocked up, this heat wave is over but we have at least…—_ Senku lifted his fingers in his “deduction” position, calculating the next wave _— Half an hour before the next one and your knot is coming down so, we could take this chance to eat something and get ready for it, mentalist…—_ He was speaking so casually about that while Gen was flustered.

_—Uh, okay! Just let me…—_ Gen said, pulling out and groaning at the sore feeling, Senku did the same, both men relieved at the breath of fresh air.

Gen still felt unsure about this whole thing. Sure, he imagined himself at the village with Senku and some kids, living a peaceful life but that was just a fantasy, a blatant fantasy. Now, the omega who clearly didn’t give a fuck about his internal turmoil, took a bite of well-preserved bread and some water while sitting at the bed, a little bit pained by the whole exercise.

_—Senku-chan, you’re so unromantic, saying things like that and not even comforting little old me! What are we gonna do? I love you so much but please don’t be so cold about it, I’m still nervous and now that I can feel you through our bond, it’s ten times worse!_ —He was behaving like a panicked schoolgirl but the mentalist couldn’t help it.

Senku chuckled, taking his hand and trying to make the mentalist to sit with him and cuddle, leaving a short kiss on his lips.

_—That’s why I’m saying it, I can feel you’re nervous… come on, Mentalist, it’s gonna be fine, we managed from worse case scenarios than having a child…_ —Senku amended, hand idly petting the alpha’s silky hair. _— Kukuku ~ ‘sides, the only thing that worries me is praying that our kid doesn’t get your horrible personality!_ —Gen pouted as Senku cackled like a maniac, devil vibes all around him.

Gen never was so in love with someone.

_—Hm! Senku-chan is so ean-may, his personality is the worst here!_ —The mentalist complained, arms closed.

_—Oh yeah? Then why are you mated with me, huh?_ —Senku countered, having too much fun with this as he got his face closer.

_—I don’t know, must be your great looks ~ Senku-chan is so handsome… as he is a meanie!_ —Gen closed the distance between them for a moment, separating just to bite at his mate’s lower lip.

_—Mm, well is that so… I should take responsibility, am I right? Poor mentalist ~—_ He moaned in Gen’s mouth, oh, another wave was close. This was going to be fun.

_—Yes! Senkie should take responsibility for making me fall in love with him… by being only mine and being with me forever ~—_

_—Of course, of course how could I forget! Any other requests, your majesty?_ —Senku bowed his head, body already climbing to the other’s, skin to skin contact making him hum pleasantly.

Gen took him by the hips, embracing the boy tightly.

_—I’ll scribble them in a papyrus by tomorrow morning, my dear, for now…. Let’s make some noise, shall we? ~_ —Gen thrusted upwards and Senku moaned-laughed, big goofy smile adorning his features.

The scientist smirked his handsome signature smirk and pressed his fingers to the bite mark con Gen’s neck, whispering in his ear and causing him to shiver violently.

_—Kukuku… this is going to be exhilarating ~—_


End file.
